What is mechanism of Whatsapp application's Contacts syncing? - android

I have a requirement like, I can be able to find the people who are using a particular app from my contacts. It is much similar like Whatsapp contacts syncing.
Whatsapp contacts is so fast & very accurate. What is the logic for it?

I'm not sure of their exact logic, but a way that I have seen it done before is as follows...
Access the phone's contacts (duh)
Get the contact that you want to add as a "friend" in your app.
Cross reference that contact's phone number with the user information that you have stored in your application's database
If that phone number exists in your database of users, then you've got a match and you can process things however you'd like from there.
That's one way of doing it, but I don't know if that's exactly how WhatsApp does it. Hope this helps!

Related

Sync contacts firebase

I'm developing a feature in my app to help users find friends who are registered and are in the contact list on the phone. Something like what instagram does here:
Does firebase have any way to synchronize and compare contacts? I think that comparing each phone contact with each database contact will not be very efficient in terms of performance.
Does firebase have any way to synchronize and compare contacts?
It does not. You should create your own system for that.
I think that comparing each phone contact with each database contact will not be very efficient in terms of performance.
Is not. In fact, is quite simple and efficient since Firebase SDK provides a method that can help you simply verify if a user exist or not in the database, this method is called exists().
For more informations, please also see my answer from this post.

Isolate Android Contact Provider

I want to create a Contact Provider so I can populate it from our database and let our business workforce to have all the customer data. That's the "easy" part.
But what I need is to isolate those contacts and avoid them to be cloned disallowing the people to copy/clone them and loosing track of that information.
Is there a way to do that? I haven't found a way to do that and I think the only way is to show the contacts in a custom Contact app. The problem with that solution is that it wouldn't be possible to know who's calling.
Is there a way to do that?
On an Android device, there will be roughly zero lines of code that knows anything about a custom ContentProvider that you create. If you do not want to share data from that provider, do not offer any UI to allow people to share data from that provider, and do not export the provider to third-party apps.
I haven't found a way to do that and I think the only way is to show the contacts in a custom Contact app
You needed to write that anyway. There are ~2 billion Android devices. None of them will have a Contacts-style app that knows anything about some custom ContentProvider that you create.
The problem with that solution is that it wouldn't be possible to know who's calling.
Correct. After all, the devices' call managers do not know anything about your custom ContentProvider.
Now, it could be that by "create a Contact Provider", you really meant "not create a Contact Provider". In this case, the "it" in "I can populate it from our database and let our business workforce to have all the customer data" might mean the standard Android ContactsContract ContentProvider. In this case, the Contacts app and in-call screens and everything else that works with contacts will work with your contacts. However, this is a system-supplied ContentProvider, exported to third-party apps, with documentation and so on. There are thousands of apps, both pre-installed and available via the Play Store and elsewhere, that can work with ContactsContract. You have no means of stopping that, and you have no means of preventing those apps from doing whatever it is that they want with this data.
IOW, you cannot satisfy "I want the Contacts app to have my contacts" and "I do not want the Contacts app to have my contacts" at the same time.

Control default contact list and messages app

Is there a way I can control what contact list and messages show? I want to make an app that if enabled will hide certain contacts or messages from certain people. I am not sure of this is doable
Please let me know if this can be done programmatically. Please note that I am referring to the default contact/messages APP that comes with android and I want to be able to control what it shows from my app
Thank you
Please note that I am referring to the default contact/messages APP that comes with android and I want to be able to control what it shows from my app
Fortunately, this is not possible, except by modifying the actual data, as noted in a comment on your question. You cannot hack into other apps like some script kiddie.
Note that, due to synchronization, deleting contacts may wind up deleting them from an upstream data source. The user may not appreciate this.
You are welcome to build your own contact app that maintains its own filtered list of contacts.

android check if a contact installed an app android (like whatsapp)

I want to let my app scan the users contactlist , and display the name of the contacts who also installed the app.
I have no idea where to begin with this . so if someone could help me getting started , that would be apreciated.
grtz
You will need to research ContentResolver because you will have to query the database containing the contacts. To do these queries, you will need the URI and column/header names for contacts db which can be found in the Contacts class.
You will also need users to register that they have your app on your own servers and the registration will need a piece of information about the user that other users would have in their contacts (the users phone number, email address, etc).
You will then need to query a few users at a time from the users contacts for this piece of information (using the ContentResolver and Contacts class), pass it to your server (as text) where it will check if they are registered, then send a message back to initial user (and possibly the match) that you found a match.
That's where you should start, and end :)
Note, you will need these permissions in the Manifest file:
android.permission.INTERNET
android.permission.READ_CONTACTS
First of all, welcome to StackOverflow. StackOverflow is for programming questions. As is such, a post asking for help should always provide a description of what you have already tried. If you haven't tried anything yet, I highly encourage you to try something, and post when you encounter a problem.
As your question stands now, we don't know what the problem is. Are you having problems scanning a contact list? Or are you having problems trying to figure out if another user has installed the app?
That being said, you will have to maintain a database for your app containing a list of people who have installed your app. When your app is launched on one device, do whatever you need to do to register the user in your database. Due to the nature of a "contact," one person's phone may only have their phone number, email address, or even just a name. This is of course something you will have to deal with in your implementation.

Possibility of a custom Contacts field with a set list of values and Contacts lookup performance

I'm pretty sure it's not viable to do what I'd like to based on some initial research, but I figured it couldn't hurt to ask the community of experts here in case someone knows a way.
I'd like to create a custom field for contacts that the user is able to edit from the main Contacts app; however, the user should only be allowed to select from a list of four specific values. A short list of string values would be ideal, but an int with a min/max range would suffice.
I'm interested in knowing if it's possible either way, but also wondering if it make sense to go this route performance wise. More specifically, would it be better to look up a contact (based on a phone number) each time a call or SMS message is received or better to store my own set of data (consisting of name, numbers, and the custom field) and just syncing contact info in a thread every so often? Or syncing contacts the first time the app is run and then registering for changes using ContentObserver?
Here is a similar question with an answer that explains how to add a custom field to a contact.
Thanks in advance.
I don't see the purpose to have your own set of data against contacts stored in your separate database, as you obviously will run into sync issues. You can use the mimetype and store whatever you want against the contact, in the manner you linked.
Whenever you want to looup contacts you can do that by using your custom mimetype. You get the contact id (from ContactsContract.Data.CONTENT_URI), and then you run another query to get the contact details (from ContactsContract.Contacts.CONTENT_URI). Please note these are different tables.
I'd like to create a custom field for contacts that the user is able to edit from the main Contacts app
I don't see that possible, editable from the main app, when you use your custom mimetypes, and you don't have much options here. The main contact app will display only the fields that are in SDK. You can store details against contacts but they won't show up in the inbuilt edit contact screen.

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